A new method for calculating the fracture strain of shear and notched specimens at various temperature and stress triaxialities

Determining a stable characteristics of material behavior under the effects of stress and temperature on the material is significantly important for optimal design as well as optimization of manufacturing process parameters in the metal forming industry. The aim of this study is to present a new method for measuring the fracture strain of shear and tensile parts in different stress triaxialities with the effect of temperature, using a VMM (Video Measuring Machine) measuring device. Aluminum 5083-H321 is used in this study. For this purpose, twenty-four different samples including shear and tensile samples for four types of triaxialities 0.2, 0.33, 0.38 and 0.55 were prepared for testing in the temperature ranges (25, 200 and 400°C). The samples are tested under the monotonic (static) loading conditions. The fracture strains are measured. The stress triaxialities are calculated the finite element simulation. The obtained results are compared with the other experimental results and also with the numerical results of the Rice and Tracy model. A good agreement are found between these results which validates the new proposed technic for measuring the shear fracture stain. Based on the results, the curve of fracture strain versus stress triaxiality has a decreasing trend at 25°C, while this curve is almost constant at 200°C and has increasing trend at 400°C.